Manufacture of pig-iron



J. P. BENNETT.

MANUFACTURE or PIG IRON.

(No Model Patented May 20, 1884.-

UNrrEn drains JOHN FRANCIS BENNETT, OF

PATENT Erich,

rrrrsnune, PENNSYLVANIA.

MANUFACTURE OF PlG lRON.

SPECIFICATION forming part of Letters Patent N0.299,01-9, dated May 20, 188%.

Application filed April 21, 1883. No model.)

To aZZ whom it may concern: H

Beitknown that I, J OHN FRANCIS BENNETT, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a certain new and useful Improvement in the Manufae ture of 'Manganese Pig-Iron; and I do hereby declare that the following is a full, clear, and eXact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form part of this specification.

My invention relates to the production of manganese pig-iron and castings thereof; and the object of my invention is to produce a pigiron having an excess of carbon by reason of the presence of manganese and a minimum of silicon, whereby such unvarying hardness is secured throughout the metal as is desirable for stamp-heads, ore-crushers, rolls for reduc ing ores and hard substances generally, and for rolling wrought-iron, copper, and other metals, and similar purposes in the arts; and hence I make the proportion of the constituent elements of my product to be 8.5 manganese, 4.45 carbon, .05 silicon, with or without phosphorus, sulphur, aluminum, calcium,and other metals, and the remaining part of the percentage iron. I attain this object by the means illustrated and the method hereinafter described.

Figure 1 represents an elevation, partly in section, of the plant essential to the successful operation of my invention; and Fig. 2 is a plan view of the same.

Similar letters refer to corresponding parts in both views.

A represents the blast-furnace to which the iron and manganese ores are fed. It is pr0- vided with tuyere-holes, through. which, by tuyers H H, I inject hot or cold air received from suitable blowers by means of annular pipe G. A down -corner, K, conducts the waste gases from the furnace to the main un derground flue.

B represents a common air reverberatory furnace heated by either solid or gaseous fuel, and having its own fire-place and chimney. The chimney I is provided with a damper, I, operated from the ground by chain 1 and lever I. The furnace B is connected with the blast-furnace A by trough A, by which the liquid pig-iron, having undergone the desired chemical changes in the latter, is introduced into the former. It is also connected with the pig-bed F by trough B, to convey the desili conized pig-iron therefrom to thepig-bed. A short spout, B, projects from the front of the furnace B, to convey desiliconized pi g-iron into a ladle, O.

G is a large ladle, mounted in bearings G O, in which it is shifted by handle G. The ladle is connected by trough 0 with a mold, E, adapted for large castings.

D represents a small ladle used for car-wheel which it is carried by the workmen and operated by a suitable handle, D.

I add manganiferous ores to the iron ores in the blast-furnace in such quantity as to yield about 8.5 manganese when smelted. Thence I convey the liquid metal into the reverberatory furnace, and keep it there until by the action of thehot gases passing over it silicon is removed. After this I either run the metal onto a pig-bed, to be made into pigs, or transfer the entire contents of the reverberatory furnace into a large ladle, whence it is transported by means of a trough to the castinglnold. Vere all impurities entirely eliminated from the product, and were it made in a cold blast charcoal-furnace, or carefully in a hotblast furnace with excess of fuel, the carbon would be increased to about 5.2 per cent. The substance is very hard and of the same strength and structure throughout.

I have learned that when pig-iron having as one of its constituents carbon, both in the combined and graphitic state, is alloyed in con1- paratively-small quantitiessay, of seven per cent.-with manganese, the carbon in the alloy is entirelyin the combined state. It is known that pig-iron having carbon in the graphitic state is soft, and, though suitable for many purposes, is not desirablein the arts when special hardness throughout the metalis required, such as for crushing and pulverizing hard minerals; neither does it subserve this purpose to employ metals having a chilled surface, because repeated blowssuch as are received by stamp-heads and anvil blocksficrack the surface and cause in time what is technically called scaling off, when applied to' carand other small castings, to the molds J J of 6 wheels, or the disjunction of the chilled from the unchilled portion of the iron, as well as because chilled metal has such unequal proportions of carbon in the chilled and unchilled portions thereof as seriously to impair the average strength of the castings.

,The percentage of manganese ore to be smelted with iron ore in a blast-furnace to give 8.5 per cent. of manganese in the resulting pig-iron varies with the quality of the iron ore and the mode of smelting, andwould have to be determined by practice. The variations are as follows: First, if the iron ores contain as much as one per cent. of phosphorus, and are smelted with a comparativelycool blast of 800 Fahrenheit, part of the manganese ore would be taken up by the phosphorus, and pass into the slag as phosphate of manganese, and part would go into the slag as silicate of manganese; consequently it would require ore containing 11.5. per cent. of metallic manganese to give 8.5 per cent. thereof in the finished product; second, if the same iron ores are smelted with a hot-blast of 1200 Fahrenheit, the same proportion of manganese would be taken up by the phosphorus, but a smaller proportion would go into the slag as silicate of manganese; therefore ore containing 10.5 per cent. of metallic manganese would give 8.5 per cent. thereof in the finished product; third, if the iron ores contain as little as one per cent. of phosphorus and but little silicon, and are smelted with a blast of 1200 Fahrenheit, it would require ore containing 9.5 per cent. of metallic manganese to give 8.5 per cent. thereof in .the resulting pig-iron; hence the most favorable conditions for reducing the percentage of metallic manganese required in the manganese ore to obtain a product containing a given per cent. of the same are iron ore comparatively free from phosphorus and containing a minimum of silica, smelted at a low pressure of blast raised to the highest attainable temperature.

atory furnace,

The invention covered by this application differs from that embodied in my'invention to be patented to me May 27, 1884, in three important particularsfirst, alarger percentage of manganic ore is fed with the iron ore; second, the molten metal is retained for a longer time in the reverberatory furnace, and by reason of feeding a higher percentage of manganese a correspondingly-higher percentage of carbon is deposited in the liquid mass; and, third, the resulting product is different in containing a higher percentage of both manganese and carbon, and a lower of phosphorus and other impurities except silicon.

I am aware that heretofore iron and manganic ores have been smelted together in a blast-furnace, and that molten metal has been run from a smelting -furnace into an openhearth furnace and there desiliconized; and this I do not broadly claim.

Having thus fully described the process of obtaining my new product, together with an incidental description of the purposes of the latter, what I claim, and desire to secure by Letters Patent of the United States, is

The manufacture of pig-iron having superior and uniform hardness, consisting of 8.5 per cent. manganese, 4.45 per cent. carbon, .05 per cent. silicon, with or without phosphorus, sulphur, aluminum, calcium,and other metals, and the remaining part of the percentage iron, by the process herein described, which consists in smelting iron and manganic ores, in the proportions herein indicated, in a blastfurnace, desiliconizing in a reverberand then casting onto a pig-bed or casting-molds, according to the form desired.

In testimony that I claim the foregoing as my own I affiX my signature in presence of two witnesses.

JOHN FRANCIS BENNETT.

Witnesses:

J. J. MoCoRMIoK, THOMAS A. McOoRMIcK.

It is hereby certified that in Letters Patent No. 299,049, granted May 20, 1884:, upon the application of John Francis Bennett, of Pittsburg, Pennsylvania, for an improvement in the Manufacture of Pig-Iron, an error appears in the printed specification requiring correction as follows: In line 32, page 2, the Word one should read .1 and that the Letters Patent should be read With this correction therein to conform to the record of the case in the Patent Office.

Signed, countersigned, and sealed this 30th day of September, A. D. 1884.

[SEAL] H. M. TELLER,

. Secretary 0 the Interior. 1 Oountersigned:

] R. G. DYRENFORTH,

, Acting Commissioner ofPciten-ts.

Correction in Letters Patent-No. 299,049

It is hereby certified that in Letters Patent No. 299,049, granted May 20, 1884, upon the application of John Francis Bennett, of Pittsburg, Pennsylvania, for an improvement in the Manufacture of Pig lronjerrors appear in the printed specification re quiring correction, as follows: In line 40, page 1, the word tuyers should read tug eves, and in line 43 the compound Word down-corner should read down-comer; and that the specification should be read with these corrections therein to make the Letters Patent conform to the record of the case in the Patent Office.

Signed, countersigned, and sealed this 27th day of May, A. D. 1884:.

[SEAL] r M. L. JOSLYN,

Acting Secretary of the Interior. Oountersigned BENJ. BUTTERWORTH,

Commissioner of Patents. 

